Internet protocol (IP) networks route packets based on network and subnet identifiers encoded in each packet. Because early IP networks could easily be divided into networks and subnets based on geographic location of equipment and because IP networks developed before widespread deployment of wireless equipment, little or no attention was given to problems associated with moving IP devices. Due to the nature of IP, a device may not attach to a network other than its home network and still receive packets normally. That is, routing protocols, firewalls, and other protocols aimed at error and fraud prevention work together to prevent packets from being delivered to a device not connected to its home network.
To overcome these problems, standards for mobile IP devices have been developed to permit mobile devices to retain a single IP address and yet receive packets when roaming in foreign networks. Specialized mobile IP software, when used by mobile devices, allows the mobile devices to register to receive packets while roaming in a foreign network. As a result of this registration, packets are redirected from the home network of the mobile device to the foreign network using a process known as tunneling. However, mobile IP software has not been widely deployed, since use of mobile IP requires specialized software and, in many cases, may disrupt the operation of other software not specifically designed for use with mobile IP. For example, a standard web browser or voice chat software may not operate properly in a mobile IP environment.